Multiple stage telescopic cylinders



April 14, 1964 N. GANCHAR ETAL 3,128,674-

MULTIPLE STAGE TELESCOPIC` CYLINDERS 2 Sheets-Sheet 1 Filed June 25,1962 April 14, 1964 f N, GANCHAR ETAL 3,128,674

MULTIPLE STAGE TELESCOPIC CYLINDERS Filed June 25, 1962 2vsneets-sheet 2United States Patent O 3,128,674 MULTIPLE STAGE TELESCOPIC CYLINDERSLeonard N. Ganchar, Canlield, and John Petro, Hubbard, Ohio, assignorsto Commercial Shearing & Stamping Company, Youngstown, Ohio Filed June25, 1962, Ser. No. 204,844 6 Claims. (Cl. 91-167) This invention relatesto multiple stage hydraulic cylinders and particularly to a multiplestage hydraulic cylinder which may be extended in controlled increments.

There has long been a need for a multiple stage telescopic cylinderwhich could be expanded in controlled positive increments and would bedouble acting. Such cylinders could be used in a variety ofapplications, such as for example, the packing cylinder in a refusetruck, in hydraulic press applications, in truck unloading devices orthe like. Conventional telescopic cylinders operate slowly over shortdistances and are difficult to control. This creates very real problemswhere rapid expansion and contraction are required over a short distanceso that only a small part of the cylinder is expanded, whereas fullexpansion is required cyclically or periodically. In the case of refusetrucks, for example, it is the practice to expand the cylinder over avery short distance periodically to move refuse into a storage portionof the truck remote from the charging door and to finally expand thecylinder over a measured portion of its length periodically to pack therefuse. In such applications, conventional telescopic hydrauliccylinders move too slowly and in the nal packing operation may expandtoo far and damage the truck assembly. No multiple stage cylindersuitable for the service herein described has, to our knowledge,heretofore been available.

The present invention provides a multiplicity of concentric doubleacting cylinders, one adapted to nest inside the other, to form atelescopic unit, a source of fluid under pressure, a piston memberadapted to tit in the smaller of said cylinders, said smaller cylindersreceiving fluid under pressure to extend the piston axially of theremaining concentric cylinders, inlet means into the remaining cylindersintroducing uid under pressure into all of the cylinders except saidsmaller cylinder whereby to expand said cylinders axially one with theother, means supplying a continuous uid pressure on all cylindersconstantly urging them toward the closed position and control meansselectively delivering uid from the source of fluid to the said `smallercylinder and the concentric cylinders to override the constant pressureurging the cylinders to the closed position.

In the foregoing general description we have set out certain objects,purposes and advantages of our invention. Other objects, purposes andadvantages will be apparent from a consideration of the followingdescription and the accompanying drawings in which:

FIGURE 1 is a longitudinal section through a telescopic cylinderaccording to our invention;

FIGURE 2 is a section through the cylinder of FIG- URE 1 with allcylinders except one partially extended;

FIGURE 3 is a section through the cylinder of FIG- URE l with allcylinders extended;

FIGURE 4 is a section through the cylinder of FIG- URE l with only thebase cylinder extended;

FIGURE 5 is a schematic showing of the cylinder of FIGURE 1 andhydraulic circuit for its operation; and

FIGURE 6 is a section on line Vl-VI of FIGURE 2.

Referring to the drawings we have illustrated a multiple stagetelescopic cylinder made up of a plurality of nesting telescopiccylinders 12, 13 and 14 surrounding an inner smaller cylinder 11carrying a piston 10. Fluid is continuously delivered from sump 15,through pump 16, and

3,128,674 Patented Apr. 14, 1964 ICC line 17 to inlet port 18 in thepiston 10. An annular passage 19 carries the fluid through the body ofthe piston 1,0 to a passageway 20, communicating from the annularpassage 19 to an annular space 21, surrounding the piston 10. Each ofthe cylinders 13, 14 and 11 are provided with similar annular spaces13a, 14a and 11a, and with spaced passages through the walls 13b and13C, 14b and 14e, and 11b and 11e. This fluid acts within the annularspace to urge the cylinders into the closed position by acting, forexample, upon the shoulder 13d of cylinder 13 and shoulder 12a ofcylinder 12, and the corresponding shoulders of each other pair ofcylinders. The uid passes around the stops 22 which are spaced annularlyon each of the cylinders to prevent their being forced off one another.

When it is desired to extend cylinders 12, 13 and 14, fluid underpressure is delivered from pump 16 through valve 24 and line 23, intothe port 25 from which it passes through axial duct 26 within thecylinder 11 into the enlarged area 27 with the cylinders 12, 13 and 14.As a result, all cylinders 12, 13 and 14 are elongated, overcoming thepressure of the fluid acting on the smaller shoulder areas 13a', forexample, of the several cylinders. n

If it is desired to operate the small piston 10 alone, uid is introducedfrom the pump 16 through valve 28, line 29, into port 30. It passesalong the annular axially extending passage 31, through port 32 into thearea 313 between the piston 10 and the cylinder 11, thus forcing thepiston 10 out of the cylinder 11.

When it is desired to operate all of the cylinders and the piston 10,both valves 24 and 28 are opened and fluid is introduced through bothports 18 and 30. When the valves 2S and 24 are closed, the uid isreturned from the enlarged area 27, back through the line 23, the valve24 and into return line 34, delivering the fluid back to sump 15 andsimultaneously from the area 33 through line 29, valve 28 and line 34 tothe sump 15. This is all accomplished by the continuous pressure whichis applied on the shoulders of the cylinders by the fluid from the line17 and port 18.

Trunnions 40 are provided on the outer housing of the cylinder 12 tomount the piston and cylinder assembly. A clevis 41 is provided on theend of piston 10 for attachment to a driving member to be operated bythe piston.

While we have illustrated and described a presently preferred embodimentof our invention in the foregoing specification it will be understoodthat this invention may be otherwise embodied within the scope of thefollowing claims.

We claim:

1. A multistage telescoping cylinder unit comprising a plurality ofconcentric cylinders, one adapted to nest inside the next adjacent oneto form a telescopic unit, a source of fluid under pressure, a pistonmember adapted to fit the smallest of said cylinders, said smallestcylinder receiving fluid under pressure to extend the piston axiallythereof, inlet means in the piston communicating with the interior ofall of the cylinders introducing uid under pressureinto the interior ofall of said cylinders except the smallest cylinder whereby the cylindersmay be expanded, means supplying a continuous fluid pressure between thewalls of the several cylinders constantly urging them towards the closedposition and control means selectively delivering fluid from the sourceof fluid to the smallest cylinder and the concentric cylinders wherebyto override the constant pressure urging the cylinders to the closedposition.

2. A multistage telescoping cylinder unit comprising a plurality ofconcentric cylinders, one adapted to nest inside the next adjacent oneto form a telescopic unit, a source of fluid under pressure, a pistonmember adapted to fit in the smallest of said cylinders, said smallestcylinder receiving uid under pressure to extend the piston axiallythereof, inlet means in the piston communicating through the piston andsmallest cylinder between the source of fluid and the interior of all ofthe cylinders introducing iuid under pressure into the interior of allof sa-id cylinders except the smallest cylinder whereby the cylindersmay be expanded, means supplying a continuous iluid pressure between theWalls of the several cylinders constantly urging them towards the closedposition and control means selectively delivering luid from the sourceof iluid to the smallest cylinder and 4the concentric cylinders wherebyto override the constant pressure urging the cylinders to the closedposition.

3. A multistage telescoping cylinder unit comprising a plurality ofconcentric cylinders, one adapted to nest inside the next adjacent oneto form a telescopic unit, a source of uid under pressure, a pistonmember adapted to tit in the smallest of said cylinders, a chamber inthe smallest cylinder at the end of the piston member, inlet means onthe piston communicating between said chamber and the source of iluid,said smallest cylinder receiving uid under pressure through said inletto extend the piston axially thereof, second inlet means in the pistoncommunicating through the piston and smallest cylinder from the sourceof tluid to the interior of all of the cylinders introducing uid underpressure into the interior of all of said cylinders except the smallestcylinder whereby the cylinders may be expanded, third inlet means in thepiston communicating With the source of fluid supplying a continuouslluid pressure between the walls of the several cylinders constantlyurging them towards the closed position and control means selectivelydelivering fluid from the source of uid to the smallest cylinder and theconcentric cylinders whereby to override the constant pressure urgingthe cylinders to the closed position.

4. A multistage telescoping cylinder unit comprising a plurality ofconcentric cylinders, one adapted to nest inside the next adjacent oneto form a telescopic unit, and spaced from each other to form an annularspace therebetween, a sealing shoulder adjacent each end of each suchcylinder sealing engaging the next adjacent cylinder, a source of uidunder pressure, a piston member adapted to t in the smallest of saidcylinders, a chamber in the smallest cylinder at the end of the pistonmember, inlet means on the piston communicating between said chamber andthe source of Huid, said smallest cylinder receiving iluid underpressure through said inlet to extend the piston axially thereof, secondinlet means in the piston communicating with the interior of all of thecylinders introducing fluid under pressure into. the interior of all ofsaid cylinders except the smallest cylinder whereby the cylinders may beexpanded, third inlet means in the piston communicating with the sourceof uid supplying a continuous fluid pressure into the annular spacesbetween the walls of the several cylinders and bearing on the sealingshoulders constantly urging the cylinders towards the closed positionand control means selectively delivering iluid from the source of fluidto the smallest cylinder and the concentric cylinders whereby tooverride the constant pressure urging the cylinders to the closedposition;

5. A multistage telescoping cylinder comprising a plurality ofconcentric cylinders of successively larger diameters, one adapted tonest inside the next adjacent larger one to form a telescopic unit, apiston member adapted to t in the smallest of said cylinders, saidsmallest cylinder receiving fluid under pressure to extend the pistonaxially thereof, inlet means in the piston communicating with theinterior of all of the cylinders admitting lluid under pressure into theinterior of all of said cylinders except the smallest cylinder wherebythe cylinders may be expanded, and inlet means admitting a continuousuid pressure between the walls of the several cylinders constantlyurging them towards the closed position.

6. A multistage telescoping cylinder comprising a plurality ofconcentric cylinders of successively larger diameter, one adapted tonest inside the next adjacent larger one to form a telescopic unit, andspaced from each other to form an annular space therebetween, a sealingshoulder adjacent each end of each said cylinder sealing engaging thenext adjacent cylinders to close said annular space, a piston memberadapted to t in the smallest of said cylinders, a chamber in thesmallest cylinder at the end of the piston member, inlet means on thepiston communicating with said chamber, said smallest cylinder receivinguid under pressure through said inlet to extend the piston axiallythereof, second inlet means in the piston communicating with theinterior of all of the cylinders introducing fluid under pressure intothe interior of all of said cylinders except the smallest cylinderwhereby the cylinders may be expanded, third inlet means in said pistonadmitting a continuous fluid pressure and means communicating throughthe walls of said cylinders between the annular spaces whereby uidadmitted by said third inlet means enters between the walls of theseveral cylinders constantly urging them towards the closed position.

No references cited.

1. A MULTISTAGE TELESCOPING CYLINDER UNIT COMPRISING A PLURALITY OFCONCENTRIC CYLINDERS, ONE ADAPTED TO NEST INSIDE THE NEXT ADJACENT ONETO FORM A TELESCOPIC UNIT, A SOURCE OF FLUID UNDER PRESSURE, A PISTONMEMBER ADAPTED TO FIT THE SMALLEST OF SAID CYLINDERS, SAID SMALLESTCYLINDER RECEIVING FLUID UNDER PRESSURE TO EXTEND THE PISTON AXIALLYTHEREOF, INLET MEANS IN THE PISTON COMMUNICATING WITH THE INTERIOR OFALL OF THE CYLINDERS INTRODUCING FLUID UNDER PRESSURE INTO THE INTERIOROF ALL OF SAID CYLINDERS EXCEPT THE SMALLEST CYLINDER WHEREBY THECYLINDERS MAY BE EXPANDED, MEANS SUPPLYING A CONTINUOUS FLUID PRESSUREBETWEEN THE WALLS OF THE SEVERAL CYLINDERS CONSTANTLY URGING THEMTOWARDS THE CLOSED POSITION AND CONTROL MEANS SELECTIVELY DELIVERINGFLUID FROM THE SOURCE OF FLUID TO THE SMALLEST CYLINDER AND THECONCENTRIC CYLINDERS WHEREBY TO OVERRIDE THE CONSTANT PRESSURE URGINGTHE CYLINDERS TO THE CLOSED POSITION.